Originally Posted by voxsartoria
Jeffery, if you read this thread: which sprang back more readily though? It seems to me that would not be the maximal degree of stretch that would distinguish the two modes of construction, but the degree of force needed to stretch and spring back that would be the issue.
Good questions. I'll have to update my blog post with this too.
The thing about the hand stitch is not that it is elastic per se- it's not, really, it's only a looping stitch. What made it superior to a lockstitch in certain seams was that a lockstitch can only stretch so much
before it breaks whereas a backstitch can stretch a lot more, and is usually done with a very thick thread which is also hard to break. So in the case of the seat seam, a hand stitch was preferable to a lockstitch until chainstitch machines came along.
In the case of the shoulder seam, I would need a very sensitive fish-scale type thing to measure the force when pulling, but I didn't notice any difference in the force needed. I would still measure in order to be accurate, but it could be said that if I don't feel it when pulling with my hands, are you going to feel any difference when wearing it?
Next, the silesia strip in the SA seam is firmly woven and semi-bias and thus stays the seam but also acts as a recovery agent- the seam bounces back after stretching whereas the A&S does not. It's like putting elastic in a seam- you stretch, and it bounces back. So in that respect, the SA seam performs better than the A&S.
The next question which remains to be asked is whether any elasticity is even REQUIRED in the shoulder seam? We are taught that it is, but think about it logically- the seam is stretching from neck to shoulder point. What movement does the body do that could expand the distance from the neck to the acromion? I can't think of any, but now that I am getting the hang of the video camera I am gong to test that too.